<i>In order to get infected you need to get exposed to an infectious dose of the virus; based on infectious dose studies with MERS and SARS, it is estimated that as few as 1000 SARS-CoV2 viral particles are needed for an infection to take hold.</i><p>As far as I know, this statement is somewhere between "completely wrong" and "very misleading". There is no minimum number of viral particles necessary for infection. Rather, there is a curve of probability of infection depending on the number of viral particles. Going by the definition in the link[1] the author provides, "The minimal infective dose is defined as the lowest number of viral particles that cause an infection in 50% of individuals (or ‘the average person’)."<p>Which is to say that there is no dose that is "safe", only doses that are less likely to cause an infection. Very brief exposures to 100 contagious people is just as likely to cause infection as a 100x exposure to one. Chance of infection is not a linear function of number of viral particles (since one can't be infected more than once) but can be approximated as linear at low numbers of particles. I feel like this makes most of the rest of the article moot.<p>Am I wrong? Is the risk of infection actually sublinear below some threshold dose? Is there thus some "safe" exposure time that can be relied on? Or is the article as wrong/misleading with regard to the risks to an individual as it seems?<p>[1] <a href="https://www.sciencemediacentre.org/expert-reaction-to-questions-about-covid-19-and-viral-load/" rel="nofollow">https://www.sciencemediacentre.org/expert-reaction-to-questi...</a>